Spark plug



Dec. 1924- 1,518,660

W. R. KREBS SPARK PLUG Filed Oct. 24, 1923 Patented Dec. 9, 1924.

UNITED STATES PATENT OFFICE.

WILLIAM R. KREBS, OF BALTIMORE, MARYLAND.

SPARK-PLUG.

Application filed October 24, 1923. Serian No. 670,428.

. one of its objects is to provide a novel form of electrode terminal whereby more efficient ignition of the charges is insured than can be had than the usual terminals afford.

Another object is to provide an electrode terminal having a plurality of points, any one of which can spark, means being employed whereby oil splashed onto the terminal will be free to drain therefrom readily, thereby preventing fouling of the spark plug and interference with its action.

A still further object is to provide improved means for adjusting the spark gap.

I "1th the foregoing and other objects in View whi chwill appeartas the description proceeds, the invention consists of certain novel details of construction and combinations of parts which will be hereinafter more fully described and pointed out in the claims, it being understood that various changes may be made in the construction and arrangement of v the parts without departing from the spirit or sacrificing any of the advantages of the invention as. claimed.

In the accompanying drawings the preferred form .of the invention has been shown;

In said drawings- Figure 1 is a view partly in elevation and partly in section through the device.

Figure 2 is adetail showing the stem of the adjustable electrode in section looking down on the top face of the electrode head.

Figure 3 is a detail ofthe adjustable electrode showing the same with the upper part in side elevation and the lower part in vertical section.

Referring to the figures by characters of reference 1 designates the usual spark plug shell havin a tubular core 2 of insulating material. he end of the shell provides a tubular electrode 3 and extending through the core 2 and the shell is a stem 4 constituting an adjustable electrode. This stem has a" circular head 5 at one end adapted to lap, although spaced from, the electrode 3, and formed in the upper face of the head are radial grooves 6. These grooves are preferably triangular in cross section and increase in depth toward the margin of the head so that oil splashed onto the head will be free to drain therefrom. The grooves provide ribs or sparking points therebetween and in the present instance eight of them are shown, as at 7 The outer end of the core 2 is recessed and is engaged by a plug or cap 8 through which the stem 4: projects. This end of the stem is screw threaded as at 9 for engagement by locking nuts 10 against which the terminal 11 of a lead ,12 can be fastened by a nut 13.

As the terminal of the adjustable electrode is self draining, it will be prevented from readily fouling and as it is grooved as described, a plurality of sparking points are provided so as-to increase the efficiency of the spark plug. By means ofthe nuts the stem'ean be adjusted longitudinally to regulate the spark gap, as w1ll be apparent.

What is claimed is 1. In a spark plug the combination with a tubular electrode, of an adjustable electrode extending therethrough and insulated therefrom, and a terminal disk-like head on the adjustable electrode lapping but spaced from the end of the tubular electrode, there being radial drain grooves in said head, said grooves being formed on the side adjacent to the tubular electrode and extending from adjacent the center of the head to the periphery and gradually widening and deeping from the center 'outward.

2. In a spark plug the combination with a tubular electrode, of an adjustable electrode extending therethrough and spaced therefrom, and a terminal disk like head on the adjustable electrode having radial draining grooves, there being a plurality of firing points between the grooves, said grooves being formed on the side adjacent the tubular electrode and extending from adjacent the center of the head to the periphery and gradually widening and deepening from the center outward.

3. In a spark plug the combination with a tubular electrode, of a disk like electrode head spaced from and lapping the end of the end o-fthe tubular electrode and having radial draining grooves, there being firing points formed by the meetin walls of the grooves,- said grooves being Formed on the side adjacent the, tubular electrode and extending from adjacent the center of the head to the periphery and gradually widening and deepening from the center outward.

4. In a spark plug the combination with a shell having a tubular electrode, of an insulating core in the shell, a cap engaging the core, an electrode adjustable in the core and cap, a disk like head at one end of the adjustable electrode having radial draining grooves forming firing points therebetween,

and means for fastening a lead to the ad- 10 justable terminal, said grooves being formed on the side adjacent the tubular electrode and extending from adjacent the center of the head to the periphery and gradually Widening and deepening from the w center outward.

In testimony whereof I afiix my signature.

WILLIAM R. KREBS. 

